Well I did the same, with apt , I managed to download everything and installed everything. After this I've downloaded the latest stable kernel for my amd platform, and installed it, everything was ok, but after that it messed up my entire system no modules for eth0, then usb etc.

The questions are :

1. Where does apt put's the downloaded upgrades? [since 200MB 2-4x a day can be a lot]2. I don't really understand this :